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Monday, May 23, 2011

IAUC nr.9209, issued on 2011, May 20, announced the discovery of a new comet (discovery magnitude 19.7) by the LINEAR survey through their 1.0-m f/2.15 reflector + CCD, on images obtained on 2011, May 14.3 The new comet has been designated C/2011 J3 (LINEAR).

After posting on the Minor Planet Center's 'NEOCP' webpage, this object has been found by several CCD astrometrists to show cometary appearance. We performed some follow-up measurements of this object while it was still listed in the NEOCP, on 2011 May 18.4 remotely from the Tzec Maun Observatory.

Stacking of 34 unfiltered exposures, 60-sec each, obtained remotely on 2011, May 18.4 from the Tzec Maun Observatory (near Mayhill, NM) through a 0.4-m, f/9 reflector + CCD, shows that this object is a comet: very diffuse coma nearly 12 arcsec in diameter, with an extremely uncertain central condensation, that hampers a precise astrometric measurement.

Thursday, May 12, 2011

CBET nr.2714, issued on 2011, May 07, announced the discovery of a new comet (discovery magnitude 19.7) by the LINEAR survey through their 1.0-m f/2.15 reflector + CCD, on images obtained on 2011, May 04.2 The new comet has been designated C/2011 J2 (LINEAR).

After posting on the Minor Planet Center's 'NEOCP' webpage, this object has been found by several CCD astrometrists to show cometary appearance. We performed some follow-up measurements of this object while it was still listed in the NEO-CP, on 2011 May 05.5 and on May 06.5 remotely from the Tzec Maun Observatory.

After stacking nine unfiltered exposures, 300-sec each, obtained remotely on 2011, May 5.5 from the Tzec Maun Observatory (near Moorook, Australia) through a 0.15-m, f/7.3 refractor + CCD, we suspected the cometary nature of this object, since it appeared "soft". On a second, confirmatory, observing session (stacking of twenty-three unfiltered exposures, 300-sec each, obtained through the same instrumentation on 2011, May 06.5) we might confirmed our suspect of a tiny coma, since the FWHM of this object was measured about 40% wider than that of nearby field stars of similar brightness.

Wednesday, May 11, 2011

A new bright comet diving into the Sun has been discovered on May. 09 by amateur astronomer Sergey Shurpakov using the images taken by SOHO spacecraft. This object belong to the famous Kreutz-group, a family of sungrazing comets that are named after German astronomer Heinrich Kreutz who first studied them in the details. These comet fragments passes extremely close to the Sun at perihelion and usually they completely evaporated during such a close approach.

Tuesday, May 10, 2011

IAUC nr.9206, issued on 2011, May 05, announced the discovery of an apparently asteroidal object (discovery magnitude 19.7) by Alex R. Gibbs on CCD images taken on April 26.3 with the Mt. Lemmon 1.5-m reflector. Gibbs suspected that this object might show slight cometary appearance.

We performed some follow-up measurements of this object while it was still listed in the NEO-CP. Stacking of 8 unfiltered exposures, 300-sec each, obtained remotely on 2011, April 27.5 from the Tzec Maun Observatory (near Moorook, Australia) through a 0.15-m, f/7.3 refractor + CCD, shows that this object is slightly diffused: its FWHM is nearly twice compared to that of nearby field stars of similar brightness.

Initially the object was given the minor-planet designation 2011 GK_71 on MPEC 2011-H41 based on a series of one-night astrometry (Apr. 14) from Spacewatch (that shows little or no cometary appearance). Other observations obtained with the Steward Observatory Bok 2.3-m f/3 reflector (+ 90Prime CCD camera) during Apr. 29.256- 29.301 in 1".3 seeing, shows the object appears nearly stellar, but with a coma diameter of 5" and a tail 9" long in p.a. 111 deg.

Comets & Asteroids news

Welcome to our Astronomy blog, devoted in particular to Comets & Asteroids and related topics. This blog is maintained by Italian amateur astronomer Ernesto Guido, particularly active in the study of the small bodies of the Solar System.